Mitsubishi Electric FR-A720-0.4K Instruction Manual page 30

4) Sink logic and source logic
⋅ In sink logic, a signal switches ON when a current flows from the corresponding signal input terminal.
Terminal SD is common to the contact input signals. Terminal SE is common to the open collector output signals.
⋅ In source logic, a signal switches ON when a current flows into the corresponding signal input terminal.
Terminal PC is common to the contact input signals. Terminal SE is common to the open collector output signals.
Current flow concerning the input/output signal
when sink logic is selected
Sink logic
Current
STF
R
STR
R
SD
Inverter
RUN
SE
• When using an external power supply for transistor output
Sink logic type
Use terminal PC as a common terminal, and perform
wiring as shown below. (Do not connect terminal SD of the
inverter with terminal 0V of the external power supply.
When using terminals PC-SD as a 24VDC power supply,
do not install an external power supply in parallel with the
inverter. Doing so may cause a malfunction in the inverter
due to undesirable currents.)
QY40P type transistor
output unit
TB1
TB2
TB17
Constant
voltage
circuit
TB18
24VDC SD
Sink
connector
DC input (sink type)
<Example: QX40>
TB1
R
R
-
+
TB17
24VDC
Current flow
Inverter
STF
24VDC
(SD)
STR
PC
Current flow
Current flow concerning the input/output signal
when source logic is selected
Source logic
PC
Current
STF
R
STR
R
Inverter
RUN
+
SE
24VDC
Current flow
Source logic type
Use terminal SD as a common terminal, and perform
wiring as shown below. (Do not connect terminal PC of the
inverter with terminal +24V of the external power supply.
When using terminals PC-SD as a 24VDC power supply,
do not install an external power supply in parallel with the
inverter. Doing so may cause a malfunction in the inverter
due to undesirable currents.)
QY80 type transistor
output unit
TB1
TB2
Constant
voltage
TB17
Fuse
circuit
TB18
Current flow
Wiring
Source
connector
DC input (source type)
<Example: QX80>
TB1
R
R
-
TB18
Inverter
PC
STF
24VDC
(SD)
STR
SD
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